1. Field of the Invention
This invention relates generally to a mechanical lock assembly of simple and manually operable character.
2. Description of the Related Art
Numerous applications exist for mechanical locks having a quick-connect, quick-release character. In such applications, it is highly desirable, from the standpoint of ease of fabrication and use, to minimize the number of moving parts. Such minimization permits the lock assembly to be simply and efficiently manufactured, as well as rendering it highly reliable, since a minimum number of moving parts decreases wear and increases service life of the lock assembly since failure modes for the device are correspondingly reduced, in relation to more complex locks and structurally intricate locks having a large number of moving parts.
In the textile industry, locking assemblies are employed to secure yarn rolls (typically called "packages" in the industry) on perforate spindles through which dye under high pressure is flowed into the yarn roll for dying of the yarn prior to its further processing. For this purpose, the perforate spindle is provided at its extremity with a threaded end rod on which is secured a lock assembly. Due to shrinkage of the yarn rolls as a result of chemical impregnation and differential temperature effects during the dying operation, simple nut locking members are impractical, since they become loosened in use, and the high pressure of the dye medium is lost as a concomitant of the resulting leakage.
Accordingly, the textile industry has adopted various types of locking assemblies which are adapted to mate with and grippingly engage the threads of the end rod. These conventional locking assemblies for dye spindle usage include various designs in which the assembly contains threaded surface cam members which exert a ratcheting engagement with the threads of the end rod when slid downwardly over the rod into abutting engagement with the outer extremity (shoulder) of the yarn roll.
A major problem which has been experienced in the use of such locking assemblies is that they tend to lock or seize in position on the threaded end rod due to the high pressure on the locking assembly exerted in the distal direction of the rod, so that the locking assembly is extremely difficult to disengage when the dying step is completed. This problem is worsened by the compression/expansion effects on the locking assembly by the yarn roll subsequent to the dying operation, particularly when a multiplicity of yarn rolls are vertically stacked on a same spindle. As a result, it is extremely difficult to "break lock" of the assembly and obtain release from the threads of the rod.
More generally, in the use of locks of all types, there is a desire to minimize the manual effort necessary to actuate the lock mechanism for locking and unlocking of the lock assembly. A very simple lock assembly with a minimal number of moving parts offers a number of advantages. First, the lock actuator/deactuator may be correspondingly simple in mechanical structure. Second, the low number of moving parts minimizes friction and inertial resistance in the operation of the lock to open and close it. Third, a minimal number of moving parts correspondingly minimizes the susceptibility of the lock assembly to environmental contaminants, e.g., airborne particulates, relative humidity, sand, soil, grit, etc., so that the locking assembly is less likely to bind or seize in use, than a locking assembly having a greater number of structural components. Fourth, the time required to actuate a lock assembly having a minimal number of parts is typically shorter than is the case with a lock assembly having a large number of coacting parts which must be sequentially or corporately engaged and motively operated.
Illustrative locking assemblies developed in recent years in the textile yarn dying industry include the locking assembly disclosed in U.S. Pat. No. 5,477,709 issued Dec. 26, 1995 to Gregory A. Rowe for "Locking Assembly for Securing and Sealing Spools to a Spindle During a Drying Operation" and the locking assembly described in U.S. Pat. No. 5,868,538 issued Feb. 9, 1999 to Roderick E. Rathbun for "Quick Release Lock Assembly." Although these respective locking assemblies represent chronologically successive improvements in the art, there is a continuing need for locking assemblies of a compact, readily manually manipulatable character, having a minimal number of moving parts, which are simple to manufacture, efficient to operate in a quick locking and quick releasing fashion, which are physically robust, and which are capable of being installed on and removed from the threaded rod of the spindle, with a minimum of manual effort.
Accordingly, it is an object of the present invention to provide an improved locking assembly meeting the foregoing criteria.
Other objects and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims.